Oxidation resistant organic substances



Patented Mar. 8, 1949 OXIDATION RESISTANT ORGANIC SUBSTANCES Roger W. Watson, Chicago, 111., assignor to Standard Oil Company, Chicago, 11]., a corporation oi' Indiana No Drawing. Application January 17, 1945, Serial No. 573,319

11 Claims. 1

The present invention relates to improvements in stabilized organic substances and the method of stabilizing the same, and more particularly to petroleum products stabilized against oxidative deterioration, especially in the presence of metals which catalyze the oxidation of such products.

. Organic substances, such as hydrocarbon products, particularly petroleum products such as lubricating oils, turbine oils, insulating oils, greases, waxes and non-viscous petroleum products such as naphthas, gasolines, fuel oils, as well as synthetic oils, are in general susceptible to deterioration brought about by oxidation. This oxidation takes places under prolonged storage at atmospheric temperatures as well as under elevated temperatures during use and is frequently accelerated by the presence of metals, such as, for example, copper and iron, which act as catalysts in promoting oxidation.

It is an object of the present invention to pro- 3 vide organic substances which are resistant to oxidative deterioration. Another object of the als which promote such oxidation. A further objcct of the present invention is to provide compositions containing petroleum products which are resistant to oxidative deterioration. A further object of the invention is to provide stabilized petroleum products. Another object of the invention is to provide a method of inhibiting the oxidative deterioration of organic substances such as petroleum products. A further object of the present invention is to provide a method of inhibiting the oxidative deterioration of petroleum products in the presence of metals.

1 hav found that the oxidative deterioration of organic substances, for example petroleum products such as lubricating oils, greases, turbine oils, transformer oils, naphthas, motor fuels, burner fuels, waxes as Well as synthetic hydrocarbon oils, can be substantially inhibited by incorporating in such products small amounts such as, for example, from about 0.001% to about 2% of the condensation products of amines, particularly polyamines containing at least two primary amino groups, especially alkyleneamines containing at least four nitrogen atoms of which at least two are primary amino nitrogen atoms, with aminosubstituted aromatic aldehydes having the general formula CHO R i (N in which X is a mono-nuclear or a polynuclear aromatic hydrocarbon, R is hydrogen, an aro- 2 group, but preferably an alkyl or aralkyl group and y is at least 1. While N-substituted amino monoor polynuclear aromatic aldehydes can be employed in the condensation, I prefer to use the N-alkylated aminobenzaldehydes having the general formula CHO in which R is hydrogen, an alkyl or aralkyl group and R1 is an alkyl or aralkyl group. The term N -alkylated as used herein and in the appended claims includes those compounds in which at least one of the amino hydrogen atoms is substituted by an alkyl or aralkyl group.

Specific examples of suitable aliphatic amines and polyalkyleneamines which can be employed in the condensation are ethylamine, butylamine, laurylamine, ethylenediamine, triethylenetetramine, propylenediamine, tetraethylenepen'tamine, tri(beta aminoethyl)-'-amine, tetra(beta aminoethyl) -ethylenediamine, aminopiperizines such as N,N'bis(beta amino ethyl) piperizine, and other aliphatic amines, particularly polyamino compounds, containing at least two primary amino nitrogen atoms. Examples of suitable N-substituted amino aromatic aldehydes are N-diethylaminobenzaldehyde, N-ethylaminobenzaldehyde, N butylaminobenzaldehyde, N dilaurylaminobenzaldehyde, N-butyl-ethylaminobenzaldehyde, N-laurylaminonaphthoic aldehyde, tetramethyl- 2,4-diaminobenzaldehyde, ,N-dihexylaminonaphthoic aldehyde, N-benzylaminobenzaldehyde, N- dimethyl 2 aminonaphthoic 3 aldehyde, N- naphthylaminobenzaldehyde, N-methyl-phenylaminobenzaldehyde, N propylnaphthylaminonaphthoic aldehyde, andthe like.

The herein-described condensation products can be readily prepared by agitating abenzene solution of molar proportions of the N-substituted amino aromatic'aldehyde and of the amino compound at about room temperature. In place of the benzene, other suitable solvents may be employed, such as hexane, ether, alcohol, carbon tetrachloride and the like. After completion of the reaction the Water formed in the reaction is drawn oil and the solvent removed from the condensation product by suitable means such as by evaporation. When the condensation is carried out in alcoholic solution in which the condensation product is relatively insoluble, the condensation product precipitates out of the alcoholic solution and is recovered as a crystalline product. In the reactions all available amine hydrogen atoms may or may not be eliminated by the condensation. By way of example tri(diethylaminobenzaldehyde) triethylenetetramine is prepared by reacting 3 mols of diethylaminobenzaldehyde with one mol. of triethylenetetramine in benzene solution at room temperature. After removal of the water of reaction, the condensation product can, if desired, be recovered from the benzene solution. Slmilarly'tri(diethylaminobenzaldehyde) -tetraethylenepe n t a m in e can be prepared by reacting 3 mols of diethylaminobenzaldehyde with one mol of tetraethylenepentamine.

The effectiveness of the herein-described'condensation products in inhibiting the oxidative deterioration of hydrocarbon oils in the presence of metals which catalyze the oxidation of such' oils is shown by the data in the following table in which the oxidative deterioration is expressed in terms of the acidity of the oil after being oxidized over a period of time in the presence of certain metals. This test is made by passing 1 liter of oxygen per hour through 10 cc. of the oil to be tested for a period of 24 hours at a. temperature of 320 F. in the presence of square centimeters of copper surface. At the end of the 24 hour period the acidity of the oil expressed in milligrams of KOH per gram of oil is determined. The following oils were subjected to this test:

A. An M. C. SAE 20W base oil.

B. A+0.1% tetramethyldiaminodlphenylmethane.

C. A+0.1% salicylaldoxime.

D. A+0.1% of the condensation product of salicylal and triethylenetetramine.

E. A+0.1% of the condensation product of 3 mols diethylaminobenzaldehyde and 1 mol of triethylenetetramine.

Acidity alter Oil Sample 24 hours Mg. KOH/gm. oil

Oil samples B, C and D contained well known products which are purported to inhibit the oxidative deterioration of petroleum oils, particularly in the presence of metal catalysts. The above data show that the condensation product of the herein-described invention; namely, the tri( diethylaminobenzaldehyde) triethylenetetramine, more effectively inhibited the oxidation of the oil than did the Well-known inhibitors.

While the above test illustrates the effect of the herein-described condensation products in inhibiting the oxidative deterioration of the viscous.

hydrocarbon oil, these products are also efiective in suppressing the oxidative deterioration, par-' ticularly in the presence of metal catalysts, of

other peteroleum products and other organic sub- 4 of carrying the same into effect, it will be readily apparent to those skilled in the art that many variations and modifications may be made therein without departing from the spirit of my invention, the scope of which is limited solely by the appended claims.

I claim:

1. A composition of matter resistant to oxidative deterioration comprising an oil, normally susceptible to oxidative deterioration in the presence of a metal which catalyzes said oxidation, and the condensation product obtained by reacting molar proportions of an amino-aromatic aldehyde, free of hydroxy substituents, having the general formula in which X is an aromatic nucleus of the group consisting of benzene and naphthalene, R is a substituent of the group consisting of a hydrogen atom, an aromatic radical of the group consisting of naphthalene and benzene, and an alkyl radical, R1 is a substituent of the group consisting of an aromatic radical of the group consisting of benzene and naphthalene, and an alkyl radical, and y is an integer of the group consisting of 1 and 2, with an amine of the group consisting of an aliphatic mono amine and a polyalkyleneamine containing at least two primary amino groups, said condensation product being used in small but sufficient quantity to inhibit the oxidative deterioration of said oil.

2. A composition of matter as described in claim 1 in which the oil is an hydrocarbon oil fraction.

3. A composition of matter resistant to oxida 'tive deterioration comprising an oil, normally susceptible to oxidative deterioration in the presence of a metal which catalyzes said oxidation, and the condensation product obtained by reacting molar proportions of an amino-aromatic aldehyde, free of hydroxy substituents, having the general formula CHO .R l x N RI v in which X is an aromatic nucleus of the group consisting of benzene and naphthalene, R is a substituent of the group consisting of a hydrogen atom, an aromatic radical of the group consisting of naphthalene and benzene, and an alkyl radical, R1 is a substituent of the group consisting of an aromatic radical of the group consisting of benzene and naphthalene, and an alkyl radical, and y is an integer of the group consisting of 1 and 2, witha polyalkyleneamine containing at least four nitrogen atoms, at least two of which are primary amino nitrogen atoms, said condensation product being used in small but sufficient quantity to inhibit the oxidative deterioration of said oil.

4. A composition of matter as described in claim 3 in which the oil is an hydrocarbon oil fraction.

5. A composition of matter resistant to oxidative deterioration comprising an oil, normally susceptible to oxidative deterioration in the presence of a metal which catalyzes said oxidation, and the condensation product obtained by reacting molar proportions of an N-alkylated aminokylated aminonaphthoicaldehyde, tree of hydroxy substituents, with a polyalkyleneamine containing at least two primary amino nitrogen atoms, said condensation product being used in small but sufficient quantity to inhibit the oxidative deterioration of said oil.

6. A composition of matter resistant to oxidative deterioration comprising an oil, normally susceptible to oxidative deterioration in the presence of a metal which catalyzes saidoxidation, and the condensation productobtained by reacting three mols of an N-alkylated amino benzaldehyde, free of hydroxy substituents, with one moi of triethyienetetramine, said condensation product being used in small but suflicient quantity to inhibit the oxidative deterioration of said 011.

7. A composition oi matter as described in claim 6 in which the oil is an hydrocarbon oil fraction.

8. A composition of matter as described in claim 6 in which the N-alkylated amino benzaldehyde is diethylaminobenzaidehyde.

9. A composition of matter resistant to oxidative deterioration comprising an oil, normally susceptible to the oxidative deterioration in the presence of a metal which catalyzes said oxidation, and a small amount, suflicient to inhibit said oxidation, of the condensation product ob- REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 2,181,122 Downing Nov. 28, 19 39 2,282,513 Downing May 12, 1942 2,300,998 white Nov. 3, 1942 2,346,663 Chenicek Apr. 18, 1944 2,361,339 White Oct. 24, 1944 2,381,952 Gubelman Aug. 14, 1945 

